Patent GB-606720-A (GB)
Title: Improvements in means for controlling a series of fluid-pressure actuated machines
IPC: B65G37/00
Filed: 1946-01-17
Abstract: 606,720. Fluid-actuated valves. DIXON, C. D., and HOLDSWORTH, J. Jan. 17, 1946, No. 1581. [Class 135] [Also in Group XXX] Valve. mechanism and operating means therefor for use in controlling a set of fluid pressure-actuated machines of the kind comprising a primary machine and a number of secondary machines which must not continue in operation after the primary machine has stopped, comprises a power-actuated valve for controlling the supply of actuating fluid to a secondary machine-operating means for controlling the supply of fluid to the valve and capable when inoperative of causing the valve to close and energizing means driven from the primary machine to hold the operating means in an operative condition as long as the primary machine is running. As shown in Fig. 1, the mechanism is applied to the control of a system of belts 1, 2, 4, 5 in a colliery working. These belts deliver to trams 7. The conveyers are driven by compressed air motors 8, 13, 14, 15 supplied with fluid from a pipe-line 9 controlled by stop valves 11, 12, 12a, 12b, 12c. Rollers 16a, 16 driven by the belts of loaders 4, 5 when rotating generate fluid pressure in the pipe 17 to keep the valves 12a, 12b, 12c open. To stop the system the valve 11 is closed. This stops the motor 8 of the belt 5 and as the belt stops the roller 16 stops, whereupon the valve 12a closes and the belt 4 stops. When the roller 16a stops, the valves 12b and 12c close, stopping the belts 1 and 2. Restarting the motor 8 restores initial conditions. Valves 12a, 12b, 12c may be operated manually to open them after they have been automatically closed. Additionally, each valve can be actuated by remote control to cause the valve to close. An operating valve is shown closed in Figs. 2 and 3. It comprises a valve housing 18 having an inlet 19 and outlet 20 with a piston-type valve 21 between, urged towards a seating 22 by a spring 23. A rod 24 keyed to the valve 21 projects into a cylinder 26 within which works a piston 27. When air under pressure is admitted, the piston displaces the rod 24 andmoves the valve 21 away from its seating 22. The compressed air at inlet 19 passes through port 28 and channel 29 to port 31 in valve chamber 32 to port 35 in valve chamber 36 and to port 42 in valve chamber 43. The valves 33, 40, 45, being disposed as shown in Fig. 3, no air can reach the port 48 leading to the upper end of the cylinder 26, which end is in communication with exhaust port 37 by way of ports 48, 44 and 38. When the valve 45 is moved to the end position, air can pass through the port 48 and causes the piston to open the valve 21. Release of the valve 45 causes the valve 21 to close under the action of the spring 23. When fluid under pressure is supplied to the connection 46, valve 40 is moved to the end position, compressed air at port 35 flows through ports 44 and 48 to the cylinder 26. Valve 21 opens and when the pressure ceases the spring 41 returns the valve 40 to the end position and valve 21 closes under the action of a spring 23. The supply of fluid to the connection 39 causes the valve 33 to move to the end position in which there is no connection between port 31 and valve chambers 36 and 43 which communicate with exhaust port 37 by way of ports 35 and 38. Hence the piston 27 cannot be operated to open the valve 21 until no fluid pressure exists at connection 39. For generating a fluid pressure to be supplied at the connection 46, the roller 16, Fig. 7, which rotates on a fixed shaft 56 has an oil reservoir 59 and a rotating cylinder pump with cylinders 60 disposed parallel to the shaft. A piston 61 under spring pressure in each cylinder reciprocates by rotation of the cylinders relative to a fixed cam 63. Suitable inlet and outlet ports are provided for the cylinders to co-operate with a distributing groove formed in the shaft. Oil from the reservoir is pumped into an axial bore in the shaft. A ball relief valve controls communication between the inner end of the bore and the port discharging into the reservoir, the outer end of the bore delivers the oil to the connection 46 on the valve 30. For supplying fluid pressure to the connection 39 on the valve block 30 an oil reservoir has a pump cylinder so that by reciprocation of the piston oil is pumped to a flexible pipe leading to a connection 39. A two-armed lever causes reciprocation, the shorter arm bears on the free end of the piston and its upper longer arm connects with a rope for remote control.